Motor vehicle window assemblies having one or more sliding panes frequently are preassembled prior to installation. Preassembly for simple insertion into a window opening in the vehicle body during vehicle assembly has been found to yield substantial cost and quality advantages. Such window assemblies typically include a metal or plastic frame to which the glass or plastic panes are mounted. The frame may be formed in place around the perimeter of the transparent panes. Such window assemblies intended for use as rear windows for pickup truck cabs, for example, typically include a frame holding one or more fixed panes and a sliding pane.
As the exterior surfaces of vehicles, including pickup trucks and the like, have grown progressively smoother and more aerodynamic, a need has developed for window assemblies suitable to present a correspondingly more integrated and flush appearance. In particular, it has become desirable to provide multi-pane window assemblies wherein at least one pane is slidably mounted, which can be integrated into a recessed window opening to provide a substantially flush overall appearance.
A window assembly for a vehicle having a flush sliding pane is shown in U.S. Pat. No. 4,850,139 to Tiesler. In the Tiesler design the sliding window is manually operated and slides in slots having wider-width portions. The wider-width portions of the slots are provided to permit one side of the sliding pane to be pulled manually out of flushness with the adjacent fixed panes and thereafter slid laterally behind an adjacent fixed pane. No power drive mechanism is suggested, and the complexity of first pulling one side of the window out of flushness followed by delayed lateral sliding would require a correspondingly complicated drive mechanism with consequent cost and reliability disadvantages.
Preassembled multi-pane window assemblies are shown in U.S. Pat. No. 4,920,698 to Friese et al. The Friese et al window assemblies are replacements for the OEM (original equipment manufacturer) window assembly originally included in a vehicle when it was new. The Friese et al window assembly includes right and left side fixed panes and a sliding center pane powered by an electric motor. In the powered sliding truck cab window assembly of Friese et al, however, the center pane is not flush with the side panes. Rather it is recessed inward toward the passenger compartment of the truck, such that it can slide laterally behind one or the other of the fixed panes to open the window. Thus, the center sliding pane does not contribute to an overall flush appearance.
In addition, the powered sliding truck cab window of the Friese et al patent discloses undesirably complex mechanisms for delivering drive power from an electric motor to slide the sliding pane between its open and closed positions. It shows, for example, a rack and pinion gear arrangement not well suited for use in powering a sliding pane which must travel not only laterally from a closed position to an open position behind an adjacent fixed pane, but also must be first off-set from a position flush with the adjacent pane when closed, i.e., toward a parallel plane for sliding to its open position. A push/pull drive cable arrangement also is shown. An interior cable cooperates with an outer sheath to drive the sliding pane through the intermediary action of a transmission mechanism which retracts or pushes out the interior cable upon actuation by the drive motor. Such push/pull cable arrangements present limitations as to the force which can be transmitted without buckling the cable. Also, such complex drive arrangements for sliding windows may present reliability concerns and increased manufacture, installation and repair costs. It would be highly desirable for meeting increasingly stringent OEM requirements of the major motor vehicle manufacturers to have a reliable, less complex drive system for a sliding window assembly, especially a sliding window assembly wherein the sliding pane in its closed position is flush with the adjacent fixed pane(s).
It is an object of the present invention to provide improved, pull/pull cable drives for multi-pane modular window assemblies having slidably mounted panes. Additional objects and optional features of the invention will be apparent from the following disclosure and detailed discussion of preferred embodiments.